Start with the fundamentals. I have published on my blog introduction series of articles for beginners (don't subscribe, it is not necessary).

https://stayux.substack.com/s/ux-design

UX is a deep topic. But from software-developer perspective you must cover the basics (if you choose so).

My book recommendation list: Laws of UX: Using Psychology to Design Better Products & Services

https://www.amazon.com/Laws-UX-Psychology-Products-Services/...

Think First: My No-Nonsense Approach to Creating Successful Products, Memorable User Experiences + Very Happy Customers

https://www.amazon.com/Think-First-No-Nonsense-Successful-Ex...

About Face: The Essentials of Interaction Design

https://www.amazon.com/About-Face-Essentials-Interaction-Des...

I hope this helps, good luck:)

I've been designing a complex desktop application.. there's not that much info out there. I found these helpful:

Designing the Win95: https://socket3.wordpress.com/2018/02/03/designing-windows-9...

Also the final design guides: https://www.ics.uci.edu/~kobsa/courses/ICS104/course-notes/M...

A (really old) book: https://www.amazon.com/About-Face-Essentials-Interaction-Des...

Another book: https://www.amazon.com/Designing-Interfaces-Patterns-Effecti...

Oddly enough these are all ancient. There hasn't been much innovation in that space though. (apart from High Dpi and Dark Mode)

Blender recently did a redesign of their UI, they have lot's of discussions about their rationale.

I have yet to read it, but I've seen good opinions on 'About face' in some threads on the topic

https://www.amazon.com/About-Face-Essentials-Interaction-Des...